Combined vacuum ignition spark advance



1954 F. w. HARTMAN, JR., ETAL 2,693,010

COMBINED VACUUM IGNITION SPARK ADVANCE Filed June 10, 1953 II/IIIIIIFrank WHart/man Jr. 5 Kali)? hSiJofinson INVENTORS I BY H M5;

9 T TOR/V5 y United States Patent Ofifice 2,698,010 Patented Dec. 28,1954 COMBINED VACUUM IGNITION SPARK ADVANCE Frank W. Hartman, Jr.,Huntington Woods, and Kalin S.

Johnson, Northville, Mich., assignors to Holley Carburetor Company,Detroit, Mich., a corporation of Michigan Application June 10, 1953,Serial No. 360,676

1 Claim. (Cl. 123-117) The object of this invention is to advance thelow tension ignition timer and the distributor of high tension currentto the individual spark plugs equally with every increase in speed andfor every decrease in inlet manifold airv pressure so that they neverget out of step. Usually the low tension timing goes ahead of the hightension distributor. I

Figure 1 shows in plan view the view looking down on Figure 2.

Figure 2 shows in cross-sectional elevation the preferred form of ourinvention.

In the figures: is the circuit breaker cam. 11 is the driven shaft. 12is the driving shaft. 14 is the passage through which inlet manifoldsuction is applied to the two casings 16 and 18 mounted on the plate 21.and 17 are two supporting plates of the two.

Plate 21 is mounted on and driven by the driving shaft 12. and 22 arethe two fabric flexible portions of the two diaphragms in the casings 16and 18. 28 is a cross bar mounted on the driven shaft 11. 24 and 26 arethe two tension springs which pull the cross bar 28 anti-clockwise toretard the spark. The clockwise rotation of this cross bar 28 rotatesthe driven shaft 11 and the cam 10 so as to advance the spark and toadvance the high tension distributor arm 31 mounted on the end of thehigh tension distributor shaft 32.

30 is the low tension circuit breaker arm. 34 is the inlet manifold. 36is the throttle valve. 38 is the suction pipe. 40, 42 are the vacuumchambers. 44 and 46 are two weights attached to 15 and 17.

Operation Centrifugal force acting on the two discs 15 and 17 in themiddle of the two diaphragms 20 and 22 tends to ad- Vance the timing ofthe cam 10 and the position of the distributor arm 31. Suctionintroduced through passage 14 serves to advance the spark as the inletmanifold pressure falls. As speed increases, the centrifugal force ofthe supporting plates 15 and 17 and the weights 44 and 46 in the middleof the two diaphragms 20 and 22 rotate the driven shaft. As the inletmanifold pressure falls, the atmospheric pressure assists thecentrifugal efiect by suction being conducted through pipe 38 from theinlet manifold 34 through passage 14 to the two suction chambers 40 and42.

It will be noted that the pipe 38 transfers the atmospheric pressure tothe inlet manifold pressure (suction) whenever the throttle 36 movesaway from the idle position in which it is shown.

In a V-l2 or V-8 engine the high tension terminals in the high tensiondistributor must be spaced 30 and 45 apart. With modern engines(overhead valves) the maximum spark advances required increase thedangers of firing in the wrong cylinder unless, as in this invention,both the low tension cam 10 and the high tension distributor arm 31 areadvanced equally.

What we claim is:

In an ignition system for an internal combustion engine having athrottle controlled inlet manifold comprising a driven shaft, a lowtension timing cam, 21 high tension distributor both rigidly connectedto and mounted on said shaft, a driving shaft, a passage therein, aconnection through which inlet manifold suction can be introduced intosaid passage, a rotating plate mounted on said driving shaft, a pair ofsuction chambers mounted on said plate located symmetrically so as toface each other and both connected to said suction passage, a movingwall in each chamber having a substantial weight, a cross bar connectedto said driven shaft, two links connected with the two ends of the crossbar and to the two moving walls, spring means adapted to oppose theeffect of the suction and centrifugal forces of the two moving walls onthe driven shaft which rotate it so as to advance the driven shaft andthereby advance equally the low tension timing cam and the high tensiondistributor arm with reference to the driving shaft.

No references cited.

